Electrodeposition of rubber under gas-removing conditions



May 4,1926. 1,583,704 v s. E. SHEPPARD ET AL msc'rnonsr'osrrxou orRUBBER UNDER GAS azuovme scum-nous I Filed June s, 1925 FIQL. v .10

an 1 Folk "rpm in um A I mwz zvrox Samuel/ E. Sheppard ($139011WEberZiw,

I ATTO EY.

Patented Mays, I

UNITED ST TES smear. a. snar'raan Ann LEON w. anrmm, ohL-aooaasrnaimwYORK, aa-

SIGNOBS TO EASTMAN KODAK COMPANY, OF BQOHESTEIF, NEW YORK, A COB-.ronarron '0! NEW roux.

' nnnc'raonnrosrrxon or Brianna UNDER oAs-annovmo connrrrons.

Application filed June 8, 1925. Serial No. 85,812.

To all whom it may mom:

ram) and LEON W. EBERLIN, subject of the King of Great Britain, and acitizen of the United States of America, respectivelhresiding atRochester, in thecounty of. on-

roe and State of New York, have invented ing i's a full, clear, andexact specification.

his invention relates to processes and apparatus for electrodepositingorganic materi'al, such as rubber for example, under such conditionsthat evolved gas is removed from the anode.

One object of the invention is to prov1de 'a process ofelectrodepositing such material in a way that will remove gases evolvedat the anode from the zone of electrode osition before they producedeleterious e ects. Another object of the invention is to provide such aprocess in which the gases, generated at the anode surface, are removedrearwardly from the zone of electrodeposition so as not to interferewith the movement of the material to the zone of electrodeposition.

the invention is to provide such a process in I which the evolved gasesmay be removed mechanically, either with or without the assistance ofchemical gas-removing expedients. Still a further object of theinvention is to provide. an a paratus in which such gas-removal isreadily effected. Still another object is to provide a porous anodethrough which the gases may be drawn away from the active anode surface.Other objects will hereinafter appear.

In the accompanying drawing, Fig. 1 is a diagrammatic cross section uponan exaggerated scale of an apparatus embod ing certain features of ourinvention an in which our process may be conveniently carried out. I

' Fig. 2 is a diagrammatic-cross section I upon an exaggerated scale ofadifierent apparatus embodying our .invention and by means of which ourprocess may be carried paratus illustrated in our prior Patent 0.

Arsu'r lorries.

V a d an'outgrowth'of the process and a i Be it known that we, SAMUEL E.Sara 1,476,374, December 4, 1923, for electrodepoatively high currentdensities. nder such circumstances gas, like oxygen, may be libsition ofrubber coatings. When rubber or equivalent organic material isdepositedv from an electroconducting aqueous emulsion thereof upon anunattackable anode, the dep-.v ositlon may be speeded by em loyingrelthis evolved gas may be wholl or substanthis removal is rearward fromthe anode surface, that is, the gas passes-away from the anode surfaceon the side of the-latter opposite to that from which the rubberpartlcles come. The result is especially useful when theelectrodepositedrubber is to be stripped from the anode surface as a smooth sheet ofsuitable continuity and uniformity.

We have found that a vacuum is the best means for removing. the gasmechanically and we prefer to carry outthis removal by means of a porousanode, to the rear side of which a vacuum isapplied. Stated differently,the porous'anode is connected at'its rearwith a chamber, the-pressure inwhich is kept materially below the pressure in. the

active electrolyte.

The porosity of the electroconducting anodes may obviously be-variedconsiderably to suit different conditions, and such anodes may be formedof different materials. We have found .that wire cloth or rated sheetmetal may be used, but in the preferred form of our-invention we emplo'porous carbon. Of course, we do not wis to be limited to these examples,except as indicated in the appended claims, since the principles of ourinvention may be applied in many different. ways. A Where metallic wirecloth is used we can employ one of a erfoliitl highly resistant metalhaving'a'mesh of ,4, to inch thickness, there being 5 pore. spacetherein; but we, of course, do

not, wish to be limited to these characteristics,- since the porosityand thickness-may vary widely without interfering with the the action ofthe vacuum tends not only to effectiveness of our invention.

Referring to Fig. 1 of thedrawing, 1 represents a container in which islocated an electroconducting aqueous emulsion 2 and a cathode 3. I 4represents the porous anode of the type describedabove. Ob- 25 viouslythe anodes may have any suitable -shape,"straight, 'curvedor irregular.In

Fi 1 it is shown as slightly curved sothat a fibric 7 drawn-across 1tWlll move smoothly and yet make good contact therewith. The anode 4 islocated in one end of *chamber .5 of any suitable or referred resist-ant gas-tight material. hamber 5, is connected by pipe iii with anysuitable vac uum source, such"=as a pump or asp rator (not shown).

The electrodeposition' may be made directlyupon the anode 4, or afabr1c'7 may be drawn through the-electrolyte over the I surface ofanode. 4 andin good contact 8, 9 and 10, the latter being preferablydriven. 'Of course,-. the movement may be continuous or intermittent.When the rubber is deposited u on the anode 4 directly, it may bestrippe therefrom, as a coherent uniform sheet afterwashing and dryingas indicated in our prior patent. .When the Q cloth is drawn slowlyacross the surface, the rubber is electrodepositcd in the meshes of; thefibers the'cloth in intimate relation to so as to impregnate it. u

' The degree of vacuum can be'- varied greatl', without interfering withthe'prac- I portion'to'the gas evolution. The gases move in Fig.1 from"the outer surfaceof an'odefi-through thefpores in the anode.

\ -"Qinto chamber 5 aridtheiie through [pipe 6' tothe'evacuatin'gapparatus. If some liquid.

.Iiis draw through-the the mode 4 into E'the chamber 5 .ifianay beremoved i by draining awayunder 'vacuum'or anyj sides. 7 suitable type,preferably above the level of therewith, sayover suitable rolls, suchas" tice 0 our invention. In fact, it is preferother suitable expedient.Usually there is no trouble from such liquid. The current densities andvoltages are preferably of the order of magnitude of those indicated inour'prior patent cited above. The nature of the current (continuous,pulsating, etc.) may also be varied so long as it is eflectivelyunidirectional,even an unbalanced A. C.

current may be useful.

Where the electrodeposition of rubber takes place into the fabric 7 theaction of the kind described in our above cited prior patent wherenon-conducting objects were rendered suitable for receiving thedeposition by impregnating them with solutions of electrolytes. Theemulsion with which the fabric is wetted or saturated performs thisfunction. It will be noted that remove the gases rearwardly from theanode zone but likewise may tend to some extent to maintain the sheet 7in contact with the anode 4. r

In Fig. 2 a difl'erent form is shown. The

vessel 1 contains one or more cathodes 3 preferably surrounding theanode on all In a stationary bearing 11 of any the emulsion 1, islocated rotatable anode 12,-say in the form of a hollow cylinder havinga collar 13 at the'top which bears upon the bearing 11. This collar maybe provided with means for actuating it, such as a pulley surface 14operated through belt '15. In the top of the anode 12 is "a closure 16through which enters a pipe 17 by means of a stuffing box 18. The pipe17 can remain stationary, while the anode 12 and I closure '16 rotate,yet stufing box 18 main tains a sufficiently gas-tightconnectionpermittingvacuum to be maintained in the hollow'anode 12. Thepipe 17 is connected with any suitable evacuating apparatus.

Electric cont-act with the anode 12 is maintained by any suitablemeans,such as a metallic conductin ring 19 mounted thereon, against 'Whicbears a brush 20 mounted on the lower face of bearing 11.

The emulsion 4, such as one of those described in our above citedpatent, or a natural or modified latex, is located around the anode tothe-desired level. The current is then'started, the vacuum being createdin the anode'12-at about the same time that the electrodepositionstarts, or even before it. The plating practice preferably follows thatdescribed in our above cited patent. WVhen 'a de osit of rubber 21. hasformed to a suita le thickness, it may be treated in the usual manner,such as by stripping it off and vulcanizin'g it or vulcanizing in situand then removing it.

Obviouslya fabric, to be impregnatedwith rubber, may be drawn acrosstherotating anodein'timed relationto its movement, this operation beingsimilar to that described '--and illustrated in connection with Flg. 1,

suitable rolls being, used.

The removal of the gas mechanically may be supplemented by the use ofchemical deoxidizing materials in the electrolyte. Thus we mayv add tothe rubber emulsion sodium or ammonium sulfite or thiosulfate.-

Sodium hydrosulfite is also very useful. The concentration of thesebodies will vary in accordance with the difliculty in combating theevolved gas. It is a'simple'adjustment for any workman, to supplysufficient reducing agents for each particular case. These reducingagents, which are preferably sulfo-bodies, form on electrolyticoxidation, polythionates which assist in maintaining dispersion ofcolloidal sulfur and may assist in the vulcanization process itself.

Having thus described our in ention, what we claim as new and desire tosecure by Letters Patent is: v

1. The process of depositing organic material on a gas-permeable anodesurface,

which comprises bringing said surface into contact with anelectroconductmg aqueous suspenslon'of said matenahJpassing a depositingelectric current through said surface and suspension,the-current-densitybeingsuch that gas is evolved-adjacent said surface, and removing saidgas rearwardly from said surface." I I Y 2. The process of'depositmgrubber on'a gas-permeable anode surface which comprises bringing saidsurface into contact with an electroconducting aqueous emulsion of saidmaterial, passing a depositing electric current throughsaid surface.and. emulsion, the current density being such that gas is evolved at theanode, and removing "said gas rearwardly from said surface.

3. The process of depositing organic material on a gas-permeable anodesurface,-

which comprises moving said surfacewhile in contact withan'electroconducting aqueous emulsion of said material, relative to saidemulsion, passing a depositing electric our ing said movement, thecurrent density being such that gas is evolved'adjacent said surface,and removing said gas rearwardly from said surface during said movement.I 4. The process of de ositin'g organic material in a fabric whiccomprises locating said fabric on a gas-permeable anode in contact withaqueous electroconductingemulsion of said material, passin a depositinelectric current through sai 'sl'irface an f'ment. rent through saidsurface and emulsion duremulsiomand removing gas liberated at the anoderearwardly fronfsaid surface away from said fabric.

5. The process of depositing rubber in a fabric which comprises movingsaidfabric across a gas-permeable anode in contact with 'ing electriccurrent through said surface and emulsion, and removing any as evolvedat said surface which is not acts upon by said -educing agent,rearwardly from said surace.

7. In an electrodeposition' apparatus for use with an electro-conductingaqueous .sus-

pension of organic material a gas-permeable anode, and'means for w1thrawmg gas rearwardly from the surface of sa1d anode.

Bill

.8. In an electrodeposition apparatus for e use withan aqueouselectroconductingemuL sion of rubber particles movable toward the anode,a porousanode, and-a vacuum chamber connected to the rear of said anode.

9,. In an electrodeposition "a paratus for fuse with an aqueouselectrocon ucting emulsion' of organic material, a gas-permeable anode,means for removing as rearwardly from the active face of sand anode, and

means for holding a fabric adjacent said .anode. In an electrode ositionapparatus for 10. use with an aqueous e 'ectroconducting emul- S1011 oforganic material, a gas-permeable ,anode, means for moving said anodeduring electrode ositionj,"-a'nd means for withdrawmg gas rom said anodeduring said move- 7 '11. In anelectrodeposition apparatus, a

gas-permeable anode, said anode including a cylindrical-portionrotatable about its axis,

and-means for withdrawing gas from the interior of said cylindricalportion during rotation of the latter.

Signed at Rochester, New York, this 2nd day of June, 1925.

SAMUEL. E. SHEPPARD. LEON w. EB RLIN;

llO

